Supply Chamber Size.

[Wrath Ordanace]

What size supply chamber do I need???

I want to fire a Nerf Vortex from a 2" Barrel, 18" long. Sprinkler valve system and I need my supply chamber to be only 1' long or less and on a 60degree down slope to hide in a stock.

Also I plan on using a smaller diameter steel tubing for the supply chamber, of course it will be regulated, but I need more info on sizes and PSI.

Any ideas?

[Hotwired]

No idea whatsoever.

A chap comes up to you with a dried pea, asks you what size rubber band he needs to ping it about with.

What kind of answer can you give him?


So. YOU are going to have to say what kind of pressure you have available, be that a foot pump, compressor or gas cylinder. Also the kind of speed the nerf is supposed to have, for which knowing the weight of it would be very helpful.

The answer will in the end be from a program called GGDT which if you search for, download and fiddle with yourself will save you time and be of interest in the future for any other air projects.

[VH_man]

i know we shouldnt spoon feed..... but.........

http://www.spudfiles.com/spud_wiki/index.php/GGDT

get the program. for pneumatic cannon constructers it is a tool that being without is almost........ life threataning........

[Wrath Ordanace]

Sorry for the illinformed question guys. I had very little sleep yesterday and wasn't even sure on some of my measurements.

Aside from the sizes I already gave. The rocket weighs approx 2.6 oz and has a diameter of 2.16 inches. I want to be able to fire the rocket at 240fps at 150-200 psi using compressed air.

Thanks for the spoonful of info with the program, I will check it out and let you know what I find. Thanks guys.

[Hotwired]

As you'll likely have not much idea about how to use GGDT I'll post a screenshot at what your setup would look like in it:



The valve data was from the GGDT library where there's data for a 2" sprinkler valve. You won't need to change anything there.

The only input you were wondering about was the chamber, you can change the ID (used 1.25") and length (used 12") on the left, maybe even fiddle with the pressure (used 200psi) to see what you get.

[vovka351]

I don't recall seeing affordable 2" sprinkler valves, nor are they usually rated to 200 psi

[Wrath Ordanace]

No, they are ussually rated for 160psi or so, but I could use the program however I am having trouble opening the executable file. So I'm still working on that.

You can get higher rated ball valves, but I really like the use of a blogun as a relief trigger mechanism.